1. Field of the Invention
The present invention relates generally to electrical coupling apparatus and sensors for the electrical power distribution field and more particularly to coupling apparatus for assembly with separable insulated connector components on power cables in power distribution systems.
2. Description of Related Art
Various apparatus have been proposed for use in making electrical connections and for sensing electrical parameters such as voltage and current in medium-voltage electrical power distribution systems. For example, this apparatus is useful to provide electrical connections and also to provide data for automated distribution systems, phasing information, troubleshooting of faulted cables, etc. Some of these arrangements utilize separable insulated connectors on power cables while others provide receiving passages through which the energized electrical cables are passed. Still other arrangements provide coupling/sensor assemblies that interfit with the conventional test point caps of elbows for cable terminations. Some of these devices utilize transformers, pick-up coils, resistive dividers and capacitive coupling to sense circuit parameters. One device, available from Lindsey Manufacturing Company of Azusa, Calif. as the Elbow Sense.TM. Voltage Monitoring Plug, utilizes a voltage monitoring plug that replaces the standard plug on 600 ampere elbow assemblies, commonly referred to as "T-body" elbows. This arrangement utilizes a precision resistive voltage divider to provide an output proportional to line-to-ground voltage. Another device available from Lindsey Manufacturing Co. is a VSB Voltage Sensing Bushing that utilizes a capacitive voltage divider. This interface bushing device is arranged to be directly affixed to a switchgear tank or the like, replacing the existing bushing that interfits with the cable-terminating elbow devices such as the 600 ampere T-body components.
Devices which capacitively couple to the test point of an elbow connector are exemplified by U.S. Pat. Nos. 4,814,933, 5,077,520 and 5,095,265.
Arrangements which utilize electrodes spaced from a cable are shown in U.S. Pat. Nos. 3,970,932, 3,991,367, 4,823,022, and 5,051,733.
Another type of voltage sensor, shown in U.S. Pat. No. 4,002,976, utilizes a capacitor having one end directly in contact with a high voltage terminal and a step-down transformer in series with the capacitor, the output of the secondary of the step-down transformer providing a voltage proportional to the terminal voltage.
While the prior art arrangements may be useful to couple electrical circuits and/or provide voltage and current information in power distribution systems, it would be desirable to provide coupling/sensing devices which interface with separable insulated connector components and are more versatile and less expensive and cumbersome.